I do notice one big change in the quilting industry over the past few years and that is the closing of many LQSs. I think the internet, big box stores/chains and the economy have contributed to the decline. What has increased are the number of large quilt shows run by corporations (Mancusco, etc).
I personally believe quilting will always be around, but like any other hobby, it will wax and wane with time. Look at scrapbooking for instance. Five years ago there were specialty shops, large areas of craft stores and "bees"...now (at least in my area of southern NH) you are hard pressed to find scrapbooking items.
I will (I hope) still be quilting 20 years from now...I'll be 78 years old then.